Project Summary/Abstract The primary goal of this project is to examine a specific form of task-related EEG activity, as a potential novel biomarker for early Alzheimer?s disease. Despite recent progress in developing biomarkers for Alzheimer?s disease, the existing suite of measures faces limitations related to invasiveness, cost, high technological demands, and low accessibility. To help address these challenges, this project will investigate EEG mid-frontal theta power (MFT), as a potentially inexpensive, non-invasive, and easily-implemented alternative. It is proposed that because Alzheimer?s disease involves the loss of cognitive and neural reserve, individuals in early stages should require increased mental exertion to achieve a given level of task performance. In turn, EEG MFT has been strongly linked to mental exertion, and as such may be over-activated in early Alzheimer?s stages. To assess the potential of MFT as a biomarker of mental exertion in early Alzheimer?s disease, this project will recruit three groups of older adults (n = 40 each; 65 years-old or older; 50% female) who are either cognitively-intact, or meet diagnostic criteria for amnestic Mild Cognitive Impairment or early Alzheimer?s disease. The first Aim of the project is to examine differences in MFT across these three groups, while controlling for differences in task performance. The second Aim of the project is to examine the sensitivity of MFT to deficits in specific cognitive and functional skills that tend to be affected in earlier disease stages. To achieve these Aims, participants will complete a single, three-hour study session, involving a brief diagnostic battery, assessments of cognitive and functional skills (instrumental activities of daily living), and resting and task-related EEG recordings. MFT will be measured using a simple task that is well-established to elicit MFT and related signals in these groups. Prior research has shown that performance on such tasks largely overlaps in these groups. On that basis, analyses will examine whether (1) individuals with Mild Cognitive Impairment and early Alzheimer?s disease exhibit greater MFT when performing at the same level as intact individuals, and (2) whether MFT differentially relates to more complex cognitive and functional skills. If successful, the proposed research could soon lead to improved screening for clinical trials, and eventually to improved early diagnosis of Alzheimer?s disease itself. Because EEG MFT is comparatively inexpensive, accessible, and easy-to-implement, it has the potential for wide and rapid dissemination. This project is consistent with the mission of the National Institute on Aging.